The Quad Mechanism has become an important pillar of the Biden administration’s “Indo-Pacific Strategy” and a key starting point in the strategic game against China. Recently，the new situation of strategic cooperation among the four countries in organizational form，cooperation field and operation mode not only reveals that a new political operation mode of alliance has been formed，but also means that the system pressure and peripheral resistance faced by China’s rise are forming “Indo-Pacific confluence” and producing “resonance effect”. Whether as a multilateral strategic cooperation platform or an international mechanism，the four-nation mechanism is highly non-neutral and has strong externalities. Under the framework of the “Indo-Pacific Strategy” of the Biden administration，the “quintessence” of the strategic interaction among the United States，Japan，Australia and India lies in the power game and institutional checks and balances against China. In view of this，China needs to respond actively，take flexible and effective measures to ensure its own development interests and security interests，and contribute to the prosperity and stability of the Indo-Pacific region.